As suggested by Dreaded Porcupine, here is a little poll to see which id that Pym has used over the years is your favorite, or the costume design you liked best (although there have been so many design for each id) and/or the one you think suited him the best. I'd also be curious to know why you voted for a specific id/costume.
On a side note, I got to thinking... are there other superheroes who had several codenames through the years? Feel free to fill me in on this as well